Channel state information reference signal processing for new radio in the unlicensed spectrum

ABSTRACT

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may select one or more sub-bands, of a plurality of sub-bands in a wideband structure of an unlicensed spectrum, for processing in association with receiving a reference signal. The one or more sub-bands may include at least one valid sub-band of a set of valid sub-bands in which the reference signal is received. The user equipment may process the one or more sub-bands in association with receiving the reference signal. Numerous other aspects are provided.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims priority to India Patent Application No.201941034601, filed on Aug. 28, 2019, entitled “CHANNEL STATEINFORMATION REFERENCE SIGNAL PROCESSING FOR NEW RADIO IN THE UNLICENSEDSPECTRUM,” and assigned to the assignee hereof. The disclosure of theprior application is considered part of and is incorporated by referenceinto this patent application.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wirelesscommunication and to techniques and apparatuses for channel stateinformation (CSI) reference signal processing for New Radio (NR) in theunlicensed spectrum.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, and/or the like). Examples of such multiple-accesstechnologies include code division multiple access (CDMA) systems, timedivision multiple access (TDMA) systems, frequency-division multipleaccess (FDMA) systems, orthogonal frequency-division multiple access(OFDMA) systems, single-carrier frequency-division multiple access(SC-FDMA) systems, time division synchronous code division multipleaccess (TD-SCDMA) systems, and Long Term Evolution (LTE).LTE/LTE-Advanced is a set of enhancements to the Universal MobileTelecommunications System (UMTS) mobile standard promulgated by theThird Generation Partnership Project (3GPP).

A wireless communication network may include a number of base stations(BSs) that can support communication for a number of user equipment(UEs). A user equipment (UE) may communicate with a base station (BS)via the downlink and uplink. The downlink (or forward link) refers tothe communication link from the BS to the UE, and the uplink (or reverselink) refers to the communication link from the UE to the BS. As will bedescribed in more detail herein, a BS may be referred to as a Node B, agNB, an access point (AP), a radio head, a transmit receive point (TRP),a New Radio (NR) BS, a 5G Node B, and/or the like.

The above multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent user equipment to communicate on a municipal, national,regional, and even global level. New Radio (NR), which may also bereferred to as 5G, is a set of enhancements to the LTE mobile standardpromulgated by the Third Generation Partnership Project (3GPP). NR isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingorthogonal frequency division multiplexing (OFDM) with a cyclic prefix(CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g.,also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) onthe uplink (UL), as well as supporting beamforming, multiple-inputmultiple-output (MIMO) antenna technology, and carrier aggregation.However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in LTE and NRtechnologies. Preferably, these improvements should be applicable toother multiple access technologies and the telecommunication standardsthat employ these technologies.

SUMMARY

In some aspects, a method of wireless communication, performed by a userequipment (UE), may include selecting one or more sub-bands, of aplurality of sub-bands in a wideband structure of an unlicensedspectrum, for processing in association with receiving a referencesignal, wherein the one or more sub-bands include at least one validsub-band of a set of valid sub-bands in which the reference signal isreceived; and processing the one or more sub-bands in association withreceiving the reference signal.

In some aspects, a UE for wireless communication may include memory andone or more processors operatively coupled to the memory. The memory andthe one or more processors may be configured to select one or moresub-bands, of a plurality of sub-bands in a wideband structure of anunlicensed spectrum, for processing in association with receiving areference signal, wherein the one or more sub-bands include at least onevalid sub-band of a set of valid sub-bands in which the reference signalis received; and process the one or more sub-bands in association withreceiving the reference signal.

In some aspects, a non-transitory computer-readable medium may store oneor more instructions for wireless communication. The one or moreinstructions, when executed by one or more processors of a UE, may causethe one or more processors to: select one or more sub-bands, of aplurality of sub-bands in a wideband structure of an unlicensedspectrum, for processing in association with receiving a referencesignal, wherein the one or more sub-bands include at least one validsub-band of a set of valid sub-bands in which the reference signal isreceived; and process the one or more sub-bands in association withreceiving the reference signal.

In some aspects, an apparatus for wireless communication may includemeans for selecting one or more sub-bands, of a plurality of sub-bandsin a wideband structure of an unlicensed spectrum, for processing inassociation with receiving a reference signal, wherein the one or moresub-bands include at least one valid sub-band of a set of validsub-bands in which the reference signal is received; and means forprocessing the one or more sub-bands in association with receiving thereference signal.

Aspects generally include a method, apparatus, system, computer programproduct, non-transitory computer-readable medium, user equipment, basestation, wireless communication device, and/or processing system assubstantially described herein with reference to and as illustrated bythe accompanying drawings and specification.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purposesof illustration and description, and not as a definition of the limitsof the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can beunderstood in detail, a more particular description, briefly summarizedabove, may be had by reference to aspects, some of which are illustratedin the appended drawings. It is to be noted, however, that the appendeddrawings illustrate only certain typical aspects of this disclosure andare therefore not to be considered limiting of its scope, for thedescription may admit to other equally effective aspects. The samereference numbers in different drawings may identify the same or similarelements.

FIG. 1 is a block diagram conceptually illustrating an example of awireless communication network, in accordance with various aspects ofthe present disclosure.

FIG. 2 is a block diagram conceptually illustrating an example of a basestation in communication with a UE in a wireless communication network,in accordance with various aspects of the present disclosure.

FIG. 3 is a diagram illustrating an example of a downlink (DL)-centricslot, in accordance with various aspects of the present disclosure.

FIG. 4 is a diagram illustrating an example of an uplink (UL)-centricslot, in accordance with various aspects of the present disclosure.

FIGS. 5A and 5B are diagrams associated with an example of channel stateinformation (CSI) reference signal processing for New Radio (NR) in theunlicensed spectrum, in accordance with various aspects of the presentdisclosure.

FIG. 6 is a diagram illustrating an example process performed, forexample, by a user equipment, in accordance with various aspects of thepresent disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

Several aspects of telecommunication systems will now be presented withreference to various apparatuses and techniques. These apparatuses andtechniques will be described in the following detailed description andillustrated in the accompanying drawings by various blocks, modules,components, circuits, steps, processes, algorithms, and/or the like(collectively referred to as “elements”). These elements may beimplemented using hardware, software, or combinations thereof. Whethersuch elements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

It should be noted that while aspects may be described herein usingterminology commonly associated with 3G and/or 4G wireless technologies,aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

FIG. 1 is a diagram illustrating a wireless network 100 in which aspectsof the present disclosure may be practiced. The wireless network 100 maybe an LTE network or some other wireless network, such as a 5G or NRnetwork. The wireless network 100 may include a number of BSs 110 (shownas BS 110 a, BS 110 b, BS 110 c, and BS 110 d) and other networkentities. ABS is an entity that communicates with user equipment (UEs)and may also be referred to as a base station, a NR BS, a Node B, a gNB,a 5G node B (NB), an access point, a transmit receive point (TRP),and/or the like. Each BS may provide communication coverage for aparticular geographic area. In 3GPP, the term “cell” can refer to acoverage area of a BS and/or a BS subsystem serving this coverage area,depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or another type of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). ABS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1, a BS 110 a may be a macro BSfor a macro cell 102 a, a BS 110 b may be a pico BS for a pico cell 102b, and a BS 110 c may be a femto BS for a femto cell 102 c. A BS maysupport one or multiple (e.g., three) cells. The terms “eNB”, “basestation”, “NR BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” maybe used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of amobile BS. In some aspects, the BSs may be interconnected to one anotherand/or to one or more other BSs or network nodes (not shown) in thewireless network 100 through various types of backhaul interfaces suchas a direct physical connection, a virtual network, and/or the likeusing any suitable transport network.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., a BS or a UE) and send a transmission of the data to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay BS 110 d may communicate with macro BS 110 a and a UE120 d in order to facilitate communication between BS 110 a and UE 120d. A relay BS may also be referred to as a relay station, a relay basestation, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/orthe like. These different types of BSs may have different transmit powerlevels, different coverage areas, and different impacts on interferencein wireless network 100. For example, macro BSs may have a high transmitpower level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relayBSs may have lower transmit power levels (e.g., 0.1 to 2 Watts).

A network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, and/or the like. A UE may be a cellularphone (e.g., a smart phone), a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, a medical device or equipment, biometric sensors/devices,wearable devices (smart watches, smart clothing, smart glasses, smartwrist bands, smart jewelry (e.g., smart ring, smart bracelet)), anentertainment device (e.g., a music or video device, or a satelliteradio), a vehicular component or sensor, smart meters/sensors,industrial manufacturing equipment, a global positioning system device,or any other suitable device that is configured to communicate via awireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolvedor enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEsinclude, for example, robots, drones, remote devices, sensors, meters,monitors, location tags, and/or the like, that may communicate with abase station, another device (e.g., remote device), or some otherentity. A wireless node may provide, for example, connectivity for or toa network (e.g., a wide area network such as Internet or a cellularnetwork) via a wired or wireless communication link. Some UEs may beconsidered Internet-of-Things (IoT) devices, and/or may be implementedas NB-IoT (narrowband internet of things) devices. Some UEs may beconsidered a Customer Premises Equipment (CPE). UE 120 may be includedinside a housing that houses components of UE 120, such as processorcomponents, memory components, and/or the like.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular RAT andmay operate on one or more frequencies. A RAT may also be referred to asa radio technology, an air interface, and/or the like. A frequency mayalso be referred to as a carrier, a frequency channel, and/or the like.Each frequency may support a single RAT in a given geographic area inorder to avoid interference between wireless networks of different RATs.In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE 120 a and UE 120e) may communicate directly using one or more sidelink channels (e.g.,without using a base station 110 as an intermediary to communicate withone another). For example, the UEs 120 may communicate usingpeer-to-peer (P2P) communications, device-to-device (D2D)communications, a vehicle-to-everything (V2X) protocol (e.g., which mayinclude a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure(V2I) protocol, and/or the like), a mesh network, and/or the like. Inthis case, the UE 120 may perform scheduling operations, resourceselection operations, and/or other operations described elsewhere hereinas being performed by the base station 110.

As indicated above, FIG. 1 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 1.

FIG. 2 shows a block diagram of a design 200 of base station 110 and UE120, which may be one of the base stations and one of the UEs in FIG. 1.Base station 110 may be equipped with T antennas 234 a through 234 t,and UE 120 may be equipped with R antennas 252 a through 252 r, where ingeneral T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from adata source 212 for one or more UEs, select one or more modulation andcoding schemes (MCS) for each UE based at least in part on channelquality indicators (CQIs) received from the UE, process (e.g., encodeand modulate) the data for each UE based at least in part on the MCS(s)selected for the UE, and provide data symbols for all UEs. Transmitprocessor 220 may also process system information (e.g., for semi-staticresource partitioning information (SRPI) and/or the like) and controlinformation (e.g., CQI requests, grants, upper layer signaling, and/orthe like) and provide overhead symbols and control symbols. Transmitprocessor 220 may also generate reference symbols for reference signals(e.g., the cell-specific reference signal (CRS)) and synchronizationsignals (e.g., the primary synchronization signal (PSS) and secondarysynchronization signal (SSS)). A transmit (TX) multiple-inputmultiple-output (MIMO) processor 230 may perform spatial processing(e.g., precoding) on the data symbols, the control symbols, the overheadsymbols, and/or the reference symbols, if applicable, and may provide Toutput symbol streams to T modulators (MODs) 232 a through 232 t. Eachmodulator 232 may process a respective output symbol stream (e.g., forOFDM and/or the like) to obtain an output sample stream. Each modulator232 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal. Tdownlink signals from modulators 232 a through 232 t may be transmittedvia T antennas 234 a through 234 t, respectively. According to variousaspects described in more detail below, the synchronization signals canbe generated with location encoding to convey additional information.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. Each demodulator 254 may condition (e.g., filter, amplify,downconvert, and digitize) a received signal to obtain input samples.Each demodulator 254 may further process the input samples (e.g., forOFDM and/or the like) to obtain received symbols. A MIMO detector 256may obtain received symbols from all R demodulators 254 a through 254 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive processor 258 may process (e.g.,demodulate and decode) the detected symbols, provide decoded data for UE120 to a data sink 260, and provide decoded control information andsystem information to a controller/processor 280. A channel processormay determine reference signal received power (RSRP), received signalstrength indicator (RSSI), reference signal received quality (RSRQ),channel quality indicator (CQI), and/or the like. In some aspects, oneor more components of UE 120 may be included in a housing.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) fromcontroller/processor 280. Transmit processor 264 may also generatereference symbols for one or more reference signals. The symbols fromtransmit processor 264 may be precoded by a TX MIMO processor 266 ifapplicable, further processed by modulators 254 a through 254 r (e.g.,for DFT-s-OFDM, CP-OFDM, and/or the like), and transmitted to basestation 110. At base station 110, the uplink signals from UE 120 andother UEs may be received by antennas 234, processed by demodulators232, detected by a MIMO detector 236 if applicable, and furtherprocessed by a receive processor 238 to obtain decoded data and controlinformation sent by UE 120. Receive processor 238 may provide thedecoded data to a data sink 239 and the decoded control information tocontroller/processor 240. Base station 110 may include communicationunit 244 and communicate to network controller 130 via communicationunit 244. Network controller 130 may include communication unit 294,controller/processor 290, and memory 292.

Controller/processor 240 of base station 110, controller/processor 280of UE 120, and/or any other component(s) of FIG. 2 may perform one ormore techniques associated with channel state information (CSI)reference signal processing options for NR in the unlicensed spectrum,as described in more detail elsewhere herein. For example,controller/processor 240 of base station 110, controller/processor 280of UE 120, and/or any other component(s) of FIG. 2 may perform or directoperations of, for example, process 600 of FIG. 6 and/or other processesas described herein. Memories 242 and 282 may store data and programcodes for base station 110 and UE 120, respectively. In some aspects,memory 242 and/or memory 282 may comprise a non-transitorycomputer-readable medium storing one or more instructions for wirelesscommunication. For example, the one or more instructions, when executedby one or more processors of the base station 110 and/or the UE 120, mayperform or direct operations of, for example, process 600 of FIG. 6and/or other processes as described herein. A scheduler 246 may scheduleUEs for data transmission on the downlink and/or uplink.

In some aspects, UE 120 may include means for selecting one or moresub-bands, of a plurality of sub-bands in a wideband structure of anunlicensed spectrum, for processing in association with receiving areference signal, wherein the one or more sub-bands include at least onevalid sub-band of a set of valid sub-bands in which the reference signalis received; means for processing the one or more sub-bands inassociation with receiving the reference signal; and/or the like. Insome aspects, such means may include one or more components of UE 120described in connection with FIG. 2, such as controller/processor 280,transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252,DEMOD 254, MIMO detector 256, receive processor 258, and/or the like.

As indicated above, FIG. 2 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 2.

FIG. 3 is a diagram 300 showing an example of a DL-centric slot orwireless communication structure. The DL-centric slot may include acontrol portion 302. The control portion 302 may exist in the initial orbeginning portion of the DL-centric slot. The control portion 302 mayinclude various scheduling information and/or control informationcorresponding to various portions of the DL-centric slot. In someconfigurations, the control portion 302 may be a physical DL controlchannel (PDCCH), as indicated in FIG. 3. In some aspects, the controlportion 302 may include legacy PDCCH information, shortened PDCCH(sPDCCH) information), a control format indicator (CFI) value (e.g.,carried on a physical control format indicator channel (PCFICH)), one ormore grants (e.g., downlink grants, uplink grants, and/or the like),and/or the like.

The DL-centric slot may also include a DL data portion 304. The DL dataportion 304 may sometimes be referred to as the payload of theDL-centric slot. The DL data portion 304 may include the communicationresources utilized to communicate DL data from the scheduling entity(e.g., UE or BS) to the subordinate entity (e.g., UE). In someconfigurations, the DL data portion 304 may be a physical DL sharedchannel (PDSCH).

The DL-centric slot may also include an UL short burst portion 306. TheUL short burst portion 306 may sometimes be referred to as an UL burst,an UL burst portion, a common UL burst, a short burst, an UL shortburst, a common UL short burst, a common UL short burst portion, and/orvarious other suitable terms. In some aspects, the UL short burstportion 306 may include one or more reference signals. Additionally, oralternatively, the UL short burst portion 306 may include feedbackinformation corresponding to various other portions of the DL-centricslot. For example, the UL short burst portion 306 may include feedbackinformation corresponding to the control portion 302 and/or the dataportion 304. Non-limiting examples of information that may be includedin the UL short burst portion 306 include an ACK signal (e.g., a PUCCHACK, a PUSCH ACK, an immediate ACK), a NACK signal (e.g., a PUCCH NACK,a PUSCH NACK, an immediate NACK), a scheduling request (SR), a bufferstatus report (BSR), a HARQ indicator, a channel state indication (CSI),a channel quality indicator (CQI), a sounding reference signal (SRS), ademodulation reference signal (DMRS), PUSCH data, and/or various othersuitable types of information. The UL short burst portion 306 mayinclude additional or alternative information, such as informationpertaining to random access channel (RACH) procedures, schedulingrequests, and various other suitable types of information.

As illustrated in FIG. 3, the end of the DL data portion 304 may beseparated in time from the beginning of the UL short burst portion 306.This time separation may sometimes be referred to as a gap, a guardperiod, a guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the subordinate entity (e.g., UE)) to ULcommunication (e.g., transmission by the subordinate entity (e.g., UE)).The foregoing is one example of a DL-centric wireless communicationstructure, and alternative structures having similar features may existwithout necessarily deviating from the aspects described herein.

As indicated above, FIG. 3 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 3.

FIG. 4 is a diagram 400 showing an example of an UL-centric slot orwireless communication structure. The UL-centric slot may include acontrol portion 402. The control portion 402 may exist in the initial orbeginning portion of the UL-centric slot. The control portion 402 inFIG. 4 may be similar to the control portion 302 described above withreference to FIG. 3. The UL-centric slot may also include an UL longburst portion 404. The UL long burst portion 404 may sometimes bereferred to as the payload of the UL-centric slot. The UL portion mayrefer to the communication resources utilized to communicate UL datafrom the subordinate entity (e.g., UE) to the scheduling entity (e.g.,UE or BS). In some configurations, the control portion 402 may be aphysical DL control channel (PDCCH).

As illustrated in FIG. 4, the end of the control portion 402 may beseparated in time from the beginning of the UL long burst portion 404.This time separation may sometimes be referred to as a gap, guardperiod, guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the scheduling entity) to UL communication(e.g., transmission by the scheduling entity).

The UL-centric slot may also include an UL short burst portion 406. TheUL short burst portion 406 in FIG. 4 may be similar to the UL shortburst portion 306 described above with reference to FIG. 3, and mayinclude any of the information described above in connection with FIG.3. The foregoing is one example of an UL-centric wireless communicationstructure, and alternative structures having similar features may existwithout necessarily deviating from the aspects described herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some aspects, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

In one example, a wireless communication structure, such as a frame, mayinclude both UL-centric slots and DL-centric slots. In this example, theratio of UL-centric slots to DL-centric slots in a frame may bedynamically adjusted based at least in part on the amount of UL data andthe amount of DL data that are transmitted. For example, if there ismore UL data, then the ratio of UL-centric slots to DL-centric slots maybe increased. Conversely, if there is more DL data, then the ratio ofUL-centric slots to DL-centric slots may be decreased.

As indicated above, FIG. 4 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 4.

Some radio access technologies (RATs), such as NR, allow operation in anunlicensed spectrum. The NR RAT for the unlicensed spectrum may bereferred to as NR-Unlicensed (NR-U). Some RATs may support differentbandwidths for sub-bands or combinations of sub-bands, such as 20 MHz,40 MHz, 60 MHz, 80 MHz, and/or the like. For example, multiple sub-bandsof 20 MHz may be combined to form a larger bandwidth, referred to as awideband. The combination of multiple sub-bands may be referred toherein as a wideband structure. A wideband structure may be a bandwidthpart of the UE (i.e., a configured bandwidth of the UE within which theUE may communicate on one or more sub-bands).

If a UE is configured with multiple sub-bands on the unlicensedspectrum, not all sub-bands may be available at a given time. Forexample, some sub-bands may be occupied by other UEs, base stations,wireless nodes, and/or other network devices. A base station or a UE mayperform a listen-before-talk (LBT) procedure to determine whether one ormore sub-bands are available for a communication. In the LBT procedure,a base station or UE may listen to a channel or a sub-band for a lengthof time, then may transmit an indication that the base station or UE hasreserved the channel or the sub-band for a time window (referred to as achannel occupancy time (COT)) if no other reservation for the channel orthe sub-band is received while listening, or if interference on thechannel or the sub-band satisfies a threshold (e.g., is below aninterference threshold). Thus, coexistence between devices onnon-centrally-scheduled channels, such as sidelink channels on theunlicensed spectrum, is enabled.

A base station may use channel state information (CSI) feedback todetermine channel conditions for a channel between the base station anda UE. For example, the base station may transmit a CSI-RS to one or moreUEs with certain characteristics that may be available to ordeterminable by the UE. Using the CSI-RS, the UE may determine CSIfeedback, such as a CSI report, that indicates the channel conditionsbetween the base station and the UE. However, in the case of unlicensedspectrum with a wideband structure, as indicated above, not allsub-bands configured for the CSI-RS may be available when the CSI-RS isto be transmitted by the base station.

One technique for resolving this issue is to define the CSI-RS to bevalid only when all sub-bands of the wideband structure are valid (i.e.,present in the COT associated with the CSI-RS transmission). In otherwords, the CSI-RS may be defined such that the base station willtransmit the CSI-RS only if all sub-bands of the wideband structure areavailable (e.g., as determined based at least in part on performing theLBT procedure in each of the sub-bands). However, this technique isquite restrictive and, as a result, the base station may not be able totransmit the CSI-RS on a majority of occasions.

Another technique for resolving the above issue is to configure the basestation to transmit the CSI-RS in valid sub-bands of the wideband (e.g.,sub-bands that passed LBT). In such a case, before transmitting theCSI-RS on the valid sub-bands, the base station may transmit a sub-bandusage indication. The sub-band usage indication can be transmitted in,for example, COT structure information (COT-SI) that is transmittedbefore the CSI-RS within the COT. The sub-band usage indication mayinclude information that identifies which sub-bands will carry CSI-RS(i.e., which sub-bands are valid sub-bands) during the COT. Here, the UEmay receive the sub-band usage indication before the CSI-RS receptionoccasion and, therefore, may have knowledge of which sub-bands are validfor CSI-RS reception. Thus, the UE may receive and process the CSI-RSaccordingly. However, UE behavior when implementing this technique hasnot been defined.

Some aspects described herein provide techniques and apparatuses forCSI-RS processing for NR-U. In some aspects, a UE may select one or moresub-bands, of a plurality of sub-bands in a wideband structure of anunlicensed spectrum, for processing in association with receiving areference signal, such as a CSI-RS. Here, the one or more sub-bands mayinclude at least one valid sub-band of a set of valid sub-bands in whichthe reference signal is received. The UE may then process the one ormore sub-bands in association with receiving the reference signal.Additional details are provided below with regard to FIGS. 5A and 5B.Notably, while the examples described herein are described in thecontext of CSI-RS, the techniques and apparatuses described herein canbe applied to another type of reference signal, such as a trackingreference signal (TRS).

FIGS. 5A and 5B are diagrams associated with an example 500 of CSI-RSprocessing for NR-U, in accordance with various aspects of the presentdisclosure.

In some aspects, as described above, a base station (e.g., base station110) may determine and provide a sub-band usage indication. As describedabove, the sub-band usage indication may include information thatidentifies a set of valid sub-bands of a plurality of sub-bands in awideband structure of an unlicensed spectrum. That is, the sub-bandusage indication may include information that identifies one or moresub-bands in the wideband structure of the unlicensed spectrum that willcarry a reference signal, such as a CSI-RS (e.g., a periodic CSI-RS(P-CSI-RS), a semi-persistent CSI-RS (SP-CSI-RS)), a TRS, and/or thelike.

In some aspects, the set of valid sub-bands may include one or moresub-band clusters, where each sub-band cluster includes one or morecontiguous valid sub-bands. For example, as shown in FIG. 5A, if thewideband structure includes sub-bands 0, 1, 2 and 3, and the basestation identifies (e.g., using the LBT procedure) sub-bands 0, 2, and 3as valid (i.e., available during the COT), then the set of validsub-bands includes two sub-band clusters—a sub-band cluster includingsub-band 0 and a sub-band cluster including sub-bands 2 and 3.

In some aspects, the processing capability of a UE may limit the numberof sub-band clusters that the UE can process. In some examples, as shownin FIG. 5B by reference number 502, the UE may transmit, to the basestation, capability information that includes information thatidentifies a maximum number of sub-band clusters that the UE can processto base station 110.

In some aspects, as noted above, the base station may determine thesub-band usage indication based at least in part on identifying the setof sub-bands as available or valid during a given COT using an LBTprocedure (e.g., based at least in part on acquiring each of the set ofsub-bands using the LBT procedure). In some aspects, as indicated inFIG. 5A, the base station may transmit the sub-band usage indication in,for example, COT-SI that is transmitted by the base station within theCOT (before the reference signal).

Thus, in some aspects, as shown in FIG. 5B by reference number 505, a UE(e.g., UE 120) may receive, from the base station, a sub-band usageindication including information that identifies a set of validsub-bands in the wideband structure of the unlicensed spectrum. In someaspects, the UE may receive the sub-band usage indication in the COT-SItransmitted by the base station within the COT (before the referencesignal is transmitted on the set of valid sub-bands).

As shown by reference number 510, in some aspects, the UE may select oneor more sub-bands, of the plurality of sub-bands in the widebandstructure of the unlicensed spectrum, for processing in association withreceiving the reference signal. In some aspects, as described in furtherdetail below, the one or more sub-bands selected by the UE may includeat least one valid sub-band of the set of valid sub-bands in which thereference signal is received (i.e., the set of valid sub-bandsidentified by the sub-band usage indication). In some aspects, selectionof the one or more sub-bands may be useful because the UE may have aperformance limitation for processing a reference signal that isreceived across multiple non-contiguous sub-band clusters.

In some aspects, the UE may select each of the plurality of sub-bands inthe wideband structure for processing. That is, in some aspects, the oneor more sub-bands selected by the UE may include each of the pluralityof sub-bands in the wideband structure. Such an aspect may be used when,for example, the UE is configured to process all sub-bands of thewideband structure (e.g., such that the UE processes each sub-bandindependently and, when the reference signal is a CSI-RS, provides a CSIreport for each sub-band). Notably, such a configuration of the UE maycause the UE to process one or more invalid sub-bands. Thus, the UE neednot receive (and the base station need not transmit) the sub-band usageindication when the UE is configured to select each of the plurality ofsub-bands in the wideband structure for processing.

In some aspects, the UE may select the set of valid sub-bands forprocessing. That is, in some aspects, the one or more sub-bands selectedby the UE may include the set of valid sub-bands only. Such an aspectmay be used when, for example, the UE is configured to process all validsub-bands of the wideband structure (e.g., such that the UE processeseach valid sub-band independently and, when the reference signal is aCSI-RS, provides a CSI report for each valid sub-band).

In some aspects, the UE may select one or more sub-bands from the set ofvalid sub-bands, where the one or more sub-bands are chosen from atleast one sub-band cluster, of one or more sub-band clusters of the setof valid sub-bands. That is, in some aspects, the one or more sub-bandsselected by the UE may include one or more sub-bands included in asubset of valid sub-bands, of the set of valid sub-bands, where the oneor more sub-bands are included in at least one sub-band cluster of oneor more sub-band clusters.

In some aspects, the at least one sub-band cluster may include a highestpriority sub-band cluster of the one or more sub-band clusters. In someaspects, the priority of the sub-band clusters may be based at least inpart on frequency (e.g., where lower or higher frequency sub-bandclusters have a higher priority) and/or based at least in part on apriority rule configured on the UE. For example, the set of validsub-bands may include three sub-band clusters. Here, the UE may identifya highest priority sub-band cluster of the three sub-band clusters, andmay select the one or more sub-bands as those included in the identifiedhighest priority sub-band cluster. In some aspects, the UE may identifymultiple sub-band clusters based at least in part on priority, and mayselect the one or more sub-bands as those included in the multiplesub-band clusters. Continuing the example described above, the UE mayidentify a next highest priority sub-band cluster of the three sub-bandclusters, and may select the one or more sub-bands as those included inthe highest priority sub-band cluster and those included in the nexthighest priority sub-band cluster. Examples of priority rules aredescribed in further detail below.

In some aspects, the at least one sub-band cluster may include a largestsub-band cluster of the one or more sub-band clusters (e.g., a sub-bandcluster with a largest bandwidth, a sub-band cluster with a greatestnumber of sub-bands, and/or the like). For example, the set of validsub-bands may include three sub-band clusters. Here, the UE may identifya largest sub-band cluster of the three sub-band clusters, and mayselect the one or more sub-bands as those included in the identifiedlargest sub-band cluster. In some aspects, the UE may identify multiplesub-band clusters based at least in part on a size of the sub-bandclusters, and may select the one or more sub-bands as those included inthe multiple sub-band clusters. Continuing the example described above,the UE may identify a next largest sub-band cluster of the threesub-band clusters, and may select the one or more sub-bands as thoseincluded in the largest sub-band cluster and those included in the nextlargest sub-band cluster. In some aspects, when multiple sub-bandclusters have a same size, the UE may identify a largest sub-bandcluster with a highest priority (e.g., a largest sub-band cluster with alowest or highest frequency, a largest sub-band cluster with a highestpriority according to a priority rule, and/or the like). In someaspects, the priority of a sub-band cluster may be determined by thepriority of the sub-bands included in the sub-band cluster (e.g., thepriority of a sub-band cluster may be based on the highest prioritysub-band in the cluster or the lowest priority sub-band in the cluster).

In some aspects, a number of sub-band clusters identified by the UE maymatch a number of sub-band clusters that can be processed by the UE. Insome aspects, the UE may transmit, to the base station, capabilityinformation indicating the number of sub-band clusters that can beprocessed by the UE, as indicated by 502 in FIG. 5B.

In some aspects, the UE may select the one or more sub-bands based atleast in part on a configuration of the UE. That is, in some aspects,the one or more sub-bands may be selected based at least in part on aconfiguration of the UE (e.g., a default or predefined configuration ofthe UE).

In some aspects, as described above, the UE may select the one or moresub-bands based at least in part on a priority rule. In some aspects,the priority rule may prioritize a given sub-band, of the plurality ofsub-bands, based at least in part on a frequency of the given sub-band.For example, the priority rule may give higher priority to lowerfrequency sub-bands or sub-band clusters.

In some aspects, the priority rule may prioritize a given sub-band, ofthe plurality of sub-bands, based at least in part on the given sub-bandincluding a synchronization signal block (SSB) or a physical broadcastchannel (PBCH). For example, the priority rule may give a higherpriority to a primary sub-band (or a sub-band cluster including theprimary sub-band) that includes the SSB or the PBCH.

In some aspects, the priority rule may prioritize a given sub-band, ofthe plurality of sub-bands, based at least in part on a predefinedpattern. For example, the priority rule may identify a priority order(e.g., [sub-band 0, sub-band 1, sub-band 2, sub-band 3]), and the UE mayselect the one or more sub-bands according to the predefined order. Insome aspects, the predefined order may cycle across COTs (e.g., from[sub-band 0, sub-band 1, sub-band 2, sub-band 3]) in a first COT, to[sub-band 1, sub-band 2, sub-band 3, sub-band 0] in a second COT, to[sub-band 2, sub-band 3, sub-band 0, sub-band 1] in a third COT, and soon) in order to dynamically vary sub-band priority across COTs.

In some aspects, the priority rule may prioritize a given sub-band, ofthe plurality of sub-bands, based at least in part on a time since amost recent channel quality indicator (CQI) report associated with thegiven sub-band. For example, the priority rule may give higher priorityto a sub-band or sub-band cluster for which CQI feedback is mostoutdated.

In some aspects, the priority rule may prioritize a given sub-band, ofthe plurality of sub-bands, based at least in part on a priority orderindicated by the base station in, for example, the COT-SI (e.g., usingan index that corresponds to a predefined priority order configured onthe UE).

In some aspects, the priority rule may use any combination of two ormore of the above example aspects to select the one or more sub-bandsfor processing.

In some aspects, the UE may transmit uplink control information (UCI)including an indication of the one or more sub-bands that are selectedby the UE (e.g., such that the base station has information thatidentifies the one or more sub-bands selected by the UE for processing).

As further shown in FIG. 5B by reference number 515, the base stationmay transmit the reference signal in the set of valid sub-bands, and theUE may receive the reference signal accordingly. For example, withreference to FIG. 5A, the base station may transmit the reference signalin sub-band 0, sub-band 2, and sub-band 3, and the UE may receive thereference signal in at least one of sub-band 0, sub-band 2, and sub-band3.

Returning to FIG. 5B, as shown by reference number 520, the UE mayprocess the one or more sub-bands (i.e., the one or more sub-bandsselected by the UE as described above) in association with receiving thereference signal. In some aspects, as shown by reference 522, the UE maytransmit CSI feedback and/or CQI feedback for at least the selected oneor more sub-bands.

For example, in some aspects, when processing the one or more sub-bands,the UE may transmit a CSI report for each of the one or more sub-bands.For example, when the reference signal is a CSI-RS, the UE may receivethe CSI-RS in the set of valid sub-bands, may generate a CSI report(e.g., including a precoding matrix indicator (PMI), a rank indicator(RI), CQI feedback, and/or the like) for each of the one or moresub-bands, and transmit the CSI report for each of the one or moresub-bands accordingly.

In some aspects, the UE may transmit CQI feedback associated with atleast one of the selected sub-bands. In some aspects, the CQI feedbackmay include sub-band CQI feedback associated with the plurality ofsub-bands in the wideband structure. In some aspects, the sub-band CQIfeedback may include CQI feedback for each sub-band of the plurality ofsub-bands in the wideband structure. Such an aspect can be used when,for example, there is a CSI size mismatch or ambiguity between the UEand the base station (e.g., such that the base station does not haveknowledge of the sub-bands for which the UE will provide CQI feedback).In some aspects, the sub-band CQI feedback may include CQI feedback foreach sub-band of the set of valid sub-bands. In some aspects, thesub-band CQI feedback may include CQI feedback for each sub-bandincluded in the one or more sub-bands processed by the UE (e.g., suchthat the UE transmits CQI feedback only for sub-bands in the sub-bandsor sub-band clusters processed by the UE according to a UE capability).

In some aspects, the CQI feedback may include wideband CQI feedback(e.g., a single CQI indication associated with the wideband structure).In some aspects, the UE may transmit the wideband CQI feedback based atleast in part on each of the plurality of sub-bands being included inthe set of valid sub-bands (i.e., the UE may transmit the wideband CQIfeedback when the set of valid sub-bands includes each of the pluralityof sub-bands in the wideband structure). In some aspects, when the setof valid sub-bands does not include each of the plurality of sub-bandsin the wideband structure, the UE may include an invalid indication inthe wideband CQI feedback. In some aspects, the UE may determine thewideband CQI feedback based at least in part on previous CQI feedbackfor at least one sub-band, of the plurality of sub-bands, that is notincluded in the set of valid sub-bands. That is, in some aspects, the UEmay use previous CQI feedback, associated with the at least one sub-bandnot valid in the COT, in association with computing the wideband CQIfeedback. In some aspects, the UE may determine the wideband CQIfeedback based at least in part on one or more sub-bands of the set ofvalid sub-bands only. That is, in some aspects, the UE may determine thewideband CQI feedback based on only a subset of the valid sub-bands(e.g., due to, for example, a UE capability limitation). In someaspects, the UE may transmit uplink control information including anindication of the one or more sub-bands based at least in part on whichthe wideband CQI feedback is determined.

In some aspects, when processing the one or more sub-bands, the UE mayperform channel estimation associated with the wideband structure. Forexample, in some aspects, the UE may perform the channel estimationbased at least in part on a wideband channel estimator. Here, the UE mayuse the wideband channel estimator even though some sub-bands of thewideband structure may not be included in the set of valid sub-bands. Insuch a case, the base station may resolve any issues (e.g., CQI feedbackissues caused by an impact of the invalid sub-bands on the widebandchannel estimate). As another example, in some aspects, the UE mayperform the channel estimation based at least in part on the set ofvalid sub-bands, or based at least in part on a set of sub-bands usedfor reporting CQI feedback, as described below.

In some aspects, a manner in which the UE performs the channelestimation is based at least in part on whether the set of validsub-bands are contiguous or non-contiguous within the widebandstructure. For example, assume that the wideband includes sub-bands 0through 3. Here, if sub-band 0, sub-band 2, and sub-band 3 are includedin the set of valid sub-bands (i.e., sub-band 1 is not included in theset of valid sub-bands such that the set of valid sub-bands includes twonon-contiguous clusters), then the UE may perform channel estimationusing a wideband channel estimator (e.g., since gain may be improveddespite the “hole” at sub-band 1). However, if only sub-band 2 andsub-band 3 are included in the set of valid sub-bands (i.e., sub-band 0and sub-band 1 are not included in the set of valid sub-bands such thatthe set of valid sub-bands includes one contiguous clusters), then theUE may perform channel estimation based at least in part on the set ofvalid sub-bands, or based at least in part on a set of sub-bands usedfor reporting CQI feedback (e.g., sub-band 2 and/or sub-band 3).

As indicated above, FIGS. 5A and 5B are provided as examples. Otherexamples may differ from what is described with respect to FIGS. 5A and5B.

FIG. 6 is a diagram illustrating an example process 600 performed, forexample, by a UE, in accordance with various aspects of the presentdisclosure. Example process 600 is an example where the UE (e.g., UE 120and/or the like) performs operations associated with CSI-RS processingfor NR-U.

As shown in FIG. 6, in some aspects, process 600 may include selectingone or more sub-bands, of a plurality of sub-bands in a widebandstructure of an unlicensed spectrum, for processing in association withreceiving a reference signal, wherein the one or more sub-bands includeat least one valid sub-band of a set of valid sub-bands in which thereference signal is received (block 610). For example, the UE (e.g.,using receive processor 258, controller/processor 280, memory 282,and/or the like) may select one or more sub-bands, of a plurality ofsub-bands in a wideband structure of an unlicensed spectrum, forprocessing in association with receiving a reference signal, asdescribed above. In some aspects, the one or more sub-bands include atleast one valid sub-band of a set of valid sub-bands in which thereference signal is received.

As further shown in FIG. 6, in some aspects, process 600 may includeprocessing the one or more sub-bands in association with receiving thereference signal (block 620). For example, the UE (e.g., using receiveprocessor 258, controller/processor 280, memory 282, and/or the like)may process the one or more sub-bands in association with receiving thereference signal, as described above.

As further shown in FIG. 6, in some aspects, process 600 may includetransmitting CSI feedback or CQI feedback for at least the selected oneor more sub-bands (block 620). For example, the UE (e.g., using transmitprocessor 264, controller/processor 280, memory 282, and/or the like)may transmit CSI feedback and/or CQI feedback for at least the selectedone or more sub-bands, as described above.

Process 600 may include additional aspects, such as any single aspect orany combination of aspects described below and/or in connection with oneor more other processes described elsewhere herein.

In a first aspect, the reference signal is a CSI-RS.

In a second aspect, alone or in combination with the first aspect, theset of valid sub-bands is determined based at least in part on asub-band usage indication.

In a third aspect, alone or in combination with one or more of the firstand second aspects, the sub-band usage indication is received in COT-SI.

In a fourth aspect, alone or in combination with one or more of thefirst through third aspects, processing the one or more sub-bandsinclude transmitting a CSI report for each of the one or more sub-bands.

In a fifth aspect, alone or in combination with one or more of the firstthrough fourth aspects, the set of valid sub-bands comprises one or moresub-bands identified as available based at least in part on an LBTprocedure.

In a sixth aspect, alone or in combination with one or more of the firstthrough fifth aspects, the one or more sub-bands include each of theplurality of sub-bands in the wideband structure.

In a seventh aspect, alone or in combination with one or more of thefirst through sixth aspects, the one or more sub-bands include the setof valid sub-bands only.

In an eighth aspect, alone or in combination with one or more of thefirst through seventh aspects, the one or more sub-bands include asubset of valid sub-bands, of the set of valid sub-bands, included in atleast one sub-band cluster of one or more sub-band clusters.

In a ninth aspect, alone or in combination with one or more of the firstthrough eighth aspects, the at least one sub-band cluster includes ahighest priority sub-band cluster, of the one or more sub-band clusters,according to a priority rule.

In a tenth aspect, alone or in combination with one or more of the firstthrough ninth aspects, the at least one sub-band cluster includes alargest sub-band cluster of the one or more sub-band clusters.

In an eleventh aspect, alone or in combination with one or more of thefirst through tenth aspects, process 600 includes transmittingcapability information indicating a number of sub-band clusters that canbe processed by the UE, wherein a number of sub-band clusters in the atleast one sub-band cluster is matching the number of sub-band clustersthat can be processed by the UE.

In a twelfth aspect, alone or in combination with one or more of thefirst through eleventh aspects, the one or more sub-bands are selectedbased at least in part on a configuration of the UE.

In a thirteenth aspect, alone or in combination with one or more of thefirst through twelfth aspects, process 600 includes transmitting uplinkcontrol information including an indication of the one or moresub-bands.

In a fourteenth aspect, alone or in combination with one or more of thefirst through thirteenth aspects, the one or more sub-bands are selectedbased at least in part on a priority rule.

In a fifteenth aspect, alone or in combination with one or more of thefirst through fourteenth aspects, the priority rule prioritizes a givensub-band, of the plurality of sub-bands, based at least in part on afrequency of the given sub-band.

In a sixteenth aspect, alone or in combination with one or more of thefirst through fifteenth aspects, the priority rule prioritizes a givensub-band, of the plurality of sub-bands, based at least in part on thegiven sub-band including a SSB or a PBCH.

In a seventeenth aspect, alone or in combination with one or more of thefirst through sixteenth aspects, the priority rule prioritizes a givensub-band, of the plurality of sub-bands, based at least in part on apredefined pattern.

In an eighteenth aspect, alone or in combination with one or more of thefirst through seventeenth aspects, the priority rule prioritizes a givensub-band, of the plurality of sub-bands, based at least in part on atime since a most recent CQI report associated with the given sub-band.

In a nineteenth aspect, alone or in combination with one or more of thefirst through eighteenth aspects, the priority rule prioritizes a givensub-band, of the plurality of sub-bands, based at least in part on apriority order indicated in COT-SI.

In a twentieth aspect, alone or in combination with one or more of thefirst through nineteenth aspects, process 600 includes transmittingsub-band CQI feedback associated with the plurality of sub-bands in thewideband structure.

In a twenty-first aspect, alone or in combination with one or more ofthe first through twentieth aspects, the sub-band CQI feedback includesCQI feedback for each sub-band of the plurality of sub-bands in thewideband structure.

In a twenty-second aspect, alone or in combination with one or more ofthe first through twenty-first aspects, the sub-band CQI feedbackincludes CQI feedback for each sub-band of the set of valid sub-bands.

In a twenty-third aspect, alone or in combination with one or more ofthe first through twenty-second aspects, the sub-band CQI feedbackincludes CQI feedback for each sub-band included in the one or moresub-bands processed by the UE.

In a twenty-fourth aspect, alone or in combination with one or more ofthe first through twenty-third aspects, process 600 includestransmitting wideband CQI feedback associated with the widebandstructure.

In a twenty-fifth aspect, alone or in combination with one or more ofthe first through twenty-fourth aspects, the wideband CQI feedback istransmitted based at least in part on each of the plurality of sub-bandsbeing included in the set of valid sub-bands.

In a twenty-sixth aspect, alone or in combination with one or more ofthe first through twenty-fifth aspects, an invalid indication isincluded in the wideband CQI feedback if at least one of the pluralityof sub-bands is not included in the set of valid sub-bands.

In a twenty-seventh aspect, alone or in combination with one or more ofthe first through twenty-sixth aspects, the wideband CQI feedback isdetermined based at least in part on previous CQI feedback for at leastone sub-band, of the plurality of sub-bands, that is not included in theset of valid sub-bands.

In a twenty-eighth aspect, alone or in combination with one or more ofthe first through twenty-seventh aspects, the wideband CQI feedback isdetermined based at least in part on one or more sub-bands of the set ofvalid sub-bands only.

In a twenty-ninth aspect, alone or in combination with one or more ofthe first through twenty-eighth aspects, process 600 includestransmitting uplink control information including an indication of theone or more sub-bands based at least in part on which the wideband CQIfeedback is determined.

In a thirtieth aspect, alone or in combination with one or more of thefirst through twenty-ninth aspects, the reference signal is a TRS.

In a thirty-first aspect, alone or in combination with one or more ofthe first through thirtieth aspects, processing the one or moresub-bands includes performing channel estimation associated with thewideband structure.

In a thirty-second aspect, alone or in combination with one or more ofthe first through thirty-first aspects, the channel estimation isperformed based at least in part on a wideband channel estimator.

In a thirty-third aspect, alone or in combination with one or more ofthe first through thirty-second aspects, the channel estimation isperformed based at least in part on: the set of valid sub-bands; or aset of sub-bands used for reporting CQI feedback.

In a thirty-fourth aspect, alone or in combination with one or more ofthe first through thirty-third aspects, a manner in which the channelestimation is performed is based at least in part on whether the set ofvalid sub-bands are contiguous or non-contiguous within the widebandstructure.

Although FIG. 6 shows example blocks of process 600, in some aspects,process 600 may include additional blocks, fewer blocks, differentblocks, or differently arranged blocks than those depicted in FIG. 6.Additionally, or alternatively, two or more of the blocks of process 600may be performed in parallel.

The foregoing disclosure provides illustration and description, but isnot intended to be exhaustive or to limit the aspects to the preciseform disclosed. Modifications and variations may be made in light of theabove disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construedas hardware, firmware, and/or a combination of hardware and software. Asused herein, a processor is implemented in hardware, firmware, and/or acombination of hardware and software.

As used herein, satisfying a threshold may, depending on the context,refer to a value being greater than the threshold, greater than or equalto the threshold, less than the threshold, less than or equal to thethreshold, equal to the threshold, not equal to the threshold, and/orthe like.

It will be apparent that systems and/or methods described herein may beimplemented in different forms of hardware, firmware, and/or acombination of hardware and software. The actual specialized controlhardware or software code used to implement these systems and/or methodsis not limiting of the aspects. Thus, the operation and behavior of thesystems and/or methods were described herein without reference tospecific software code—it being understood that software and hardwarecan be designed to implement the systems and/or methods based, at leastin part, on the description herein.

Even though particular combinations of features are recited in theclaims and/or disclosed in the specification, these combinations are notintended to limit the disclosure of various aspects. In fact, many ofthese features may be combined in ways not specifically recited in theclaims and/or disclosed in the specification. Although each dependentclaim listed below may directly depend on only one claim, the disclosureof various aspects includes each dependent claim in combination withevery other claim in the claim set. A phrase referring to “at least oneof” a list of items refers to any combination of those items, includingsingle members. As an example, “at least one of: a, b, or c” is intendedto cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combinationwith multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c,a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering ofa, b, and c).

No element, act, or instruction used herein should be construed ascritical or essential unless explicitly described as such. Also, as usedherein, the articles “a” and “an” are intended to include one or moreitems, and may be used interchangeably with “one or more.” Furthermore,as used herein, the terms “set” and “group” are intended to include oneor more items (e.g., related items, unrelated items, a combination ofrelated and unrelated items, and/or the like), and may be usedinterchangeably with “one or more.” Where only one item is intended, thephrase “only one” or similar language is used. Also, as used herein, theterms “has,” “have,” “having,” and/or the like are intended to beopen-ended terms. Further, the phrase “based on” is intended to mean“based, at least in part, on” unless explicitly stated otherwise.

What is claimed is:
 1. A method of wireless communication performed by auser equipment (UE), comprising: selecting one or more sub-bands, of aplurality of sub-bands in a wideband structure of an unlicensedspectrum, for processing in association with receiving a referencesignal, wherein the one or more sub-bands include at least one validsub-band of a set of valid sub-bands in which the reference signal isreceived; and processing the one or more sub-bands in association withreceiving the reference signal.
 2. The method of claim 1, wherein thereference signal is a channel state information reference signal(CSI-RS).
 3. The method of claim 1, wherein the set of valid sub-bandsis determined based at least in part on a sub-band usage indication. 4.The method of claim 3, wherein the sub-band usage indication is receivedin channel occupancy time structure information (COT-SI).
 5. The methodof claim 1, wherein processing the one or more sub-bands includetransmitting a channel state information (CSI) report for each of theone or more sub-bands.
 6. The method of claim 1, wherein the one or moresub-bands include each of the plurality of sub-bands in the widebandstructure.
 7. The method of claim 1, wherein the one or more sub-bandsinclude the set of valid sub-bands only.
 8. The method of claim 1,wherein the one or more sub-bands include a subset of valid sub-bands,of the set of valid sub-bands, included in at least one sub-band clusterof one or more sub-band clusters.
 9. The method of claim 8, wherein theat least one sub-band cluster includes a largest sub-band cluster of theone or more sub-band clusters.
 10. The method of claim 8, furthercomprising: transmitting capability information indicating a number ofsub-band clusters that can be processed by the UE, wherein a number ofsub-band clusters in the at least one sub-band cluster matches thenumber of sub-band clusters that can be processed by the UE.
 11. Themethod of claim 1, wherein the one or more sub-bands are selected basedat least in part on at least one of a configuration of the UE or apriority rule.
 12. The method of claim 11, wherein the priority ruleprioritizes a given sub-band, of the plurality of sub-bands, based atleast in part on a frequency of the given sub-band.
 13. The method ofclaim 11, wherein the priority rule prioritizes a given sub-band, of theplurality of sub-bands, based at least in part on the given sub-bandincluding a synchronization signal block (SSB) or a physical broadcastchannel (PBCH).
 14. The method of claim 1, further comprising:transmitting sub-band channel quality indicator (CQI) feedbackassociated with the plurality of sub-bands in the wideband structure.15. The method of claim 14, wherein the sub-band CQI feedback includesCQI feedback for each sub-band of the plurality of sub-bands in thewideband structure or for each sub-band of the set of valid sub-bands.16. The method of claim 1, further comprising: transmitting widebandchannel quality indicator (CQI) feedback associated with the widebandstructure.
 17. The method of claim 16, wherein the wideband CQI feedbackis transmitted based at least in part on each of the plurality ofsub-bands being included in the set of valid sub-bands.
 18. The methodof claim 16, wherein an invalid indication is included in the widebandCQI feedback if at least one of the plurality of sub-bands is notincluded in the set of valid sub-bands.
 19. The method of claim 16,wherein the wideband CQI feedback is determined based at least in parton one or more sub-bands of the set of valid sub-bands only.
 20. Themethod of claim 16, further comprising: transmitting uplink controlinformation including an indication of the one or more sub-bands basedat least in part on which the wideband CQI feedback is determined. 21.The method of claim 1, wherein the reference signal is a trackingreference signal (TRS).
 22. The method of claim 1, wherein processingthe one or more sub-bands includes performing channel estimationassociated with the wideband structure, the channel estimation beingperformed based at least in part on at least one of: a wideband channelestimator, the set of valid sub-bands, or a set of sub-bands used forreporting channel quality indicator (CQI) feedback.
 23. A user equipment(UE) for wireless communication, comprising: a memory; and one or moreprocessors operatively coupled to the memory, the memory and the one ormore processors configured to: select one or more sub-bands, of aplurality of sub-bands in a wideband structure of an unlicensedspectrum, for processing in association with receiving a referencesignal, wherein the one or more sub-bands include at least one validsub-band of a set of valid sub-bands in which the reference signal isreceived; and process the one or more sub-bands in association withreceiving the reference signal.
 24. The UE of claim 23, wherein thereference signal is a channel state information reference signal(CSI-RS).
 25. The UE of claim 23, wherein the set of valid sub-bands isdetermined based at least in part on a sub-band usage indication. 26.The UE of claim 23, wherein processing the one or more sub-bandsincludes transmitting a channel state information (CSI) report for eachof the one or more sub-bands.
 27. The UE of claim 23, wherein the one ormore sub-bands include each of the plurality of sub-bands in thewideband structure.
 28. The UE of claim 23, wherein the one or moresub-bands include the set of valid sub-bands only.
 29. The UE of claim23, wherein the one or more sub-bands include a subset of validsub-bands, of the set of valid sub-bands, included in at least onesub-band cluster of one or more sub-band clusters.
 30. The UE of claim23, wherein the one or more sub-bands are selected based at least inpart on at least one of a configuration of the UE or a priority rule.